How to use SUM with INNER JOIN from two different tables

Question

I am stuck on a query where i have to show list of manufacturers and the Amount of Loan they took and Amount of Refund they returned. i have generated the query but i want to sum total no: of refunds of a manufacturer and total no: of Loans manufacturer has taken. and the difference , that is LoanTaken - RefundAmount = Remaining Amount. If its possible in the query.

SELECT MM.*, ML.*, MR.*  FROM microfinance_manufacturers AS MM 
                INNER JOIN manufacturer_loans AS ML ON MM.ManufacturerId = Ml.ManufacturerId 
                INNER JOIN manufacturer_refunds AS MR ON MM.ManufacturerId = MR.manufacturerId
                WHERE 1 = 1

ManufacturerId  FirstName  LastName  Gender  Religion  PhoneNumber  EmailAddress  Notes              CustomerAddedDateTime  manufacturerTypeId  manufacturerRoles                                                                                                                                                                                                                                                                                                                                                                                 LoanID  ManufacturerId  LoanAmount  LoanDate    RefundId  manufacturerId  RefundAmount  RefundDate  

---

         5  Saud       Jibran         0         0  8475983748G  HFDKJFH       VGHJXGVHJD         2015-04-29 14:12:20                    21  O:16:"clsEmployeeRoles":68:{s:56:"aEmployeeRole_Organization_RegionalHierarchy_RegionTypes";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:52:"aEmployeeRole_Organization_RegionalHierarchy_Regions";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:69:"aEmployeeRole_Organization_RegionalHierarchy_Regions_RegionStatistics";a:2:{i:0;i:0;i:2;i:0;}s:82:"aEmployeeRole_Organization_RegionalHierarchy_Regions_     6               5  65644343:1:"2015-05-06Em       6               5  77744s_Station2015-05-06:{
         5  Saud       Jibran         0         0  8475983748G  HFDKJFH       VGHJXGVHJD         2015-04-29 14:12:20                    21  O:16:"clsEmployeeRoles":68:{s:56:"aEmployeeRole_Organization_RegionalHierarchy_RegionTypes";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:52:"aEmployeeRole_Organization_RegionalHierarchy_Regions";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:69:"aEmployeeRole_Organization_RegionalHierarchy_Regions_RegionStatistics";a:2:{i:0;i:0;i:2;i:0;}s:82:"aEmployeeRole_Organization_RegionalHierarchy_Regions_    13               5  543543;s:1:"2015-05-07Em       6               5  77744s_Station2015-05-06:{
         7  Naveed     Ahmed          0         0  847893       hfkjhfskj     fjksddshkfjdshfkj  2015-04-29 14:22:16                    19  O:16:"clsEmployeeRoles":68:{s:56:"aEmployeeRole_Organization_RegionalHierarchy_RegionTypes";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:52:"aEmployeeRole_Organization_RegionalHierarchy_Regions";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:69:"aEmployeeRole_Organization_RegionalHierarchy_Regions_RegionStatistics";a:2:{i:0;i:0;i:2;i:0;}s:82:"aEmployeeRole_Organization_RegionalHierarchy_Regions_    16               7  8798u656:1:"2015-05-07Em       9               7  4354334Station2015-05-07:{
         7  Naveed     Ahmed          0         0  847893       hfkjhfskj     fjksddshkfjdshfkj  2015-04-29 14:22:16                    19  O:16:"clsEmployeeRoles":68:{s:56:"aEmployeeRole_Organization_RegionalHierarchy_RegionTypes";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:52:"aEmployeeRole_Organization_RegionalHierarchy_Regions";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:69:"aEmployeeRole_Organization_RegionalHierarchy_Regions_RegionStatistics";a:2:{i:0;i:0;i:2;i:0;}s:82:"aEmployeeRole_Organization_RegionalHierarchy_Regions_    16               7  8798u656:1:"2015-05-07Em      10               7  896789798ation2015-05-07:{
         7  Naveed     Ahmed          0         0  847893       hfkjhfskj     fjksddshkfjdshfkj  2015-04-29 14:22:16                    19  O:16:"clsEmployeeRoles":68:{s:56:"aEmployeeRole_Organization_RegionalHierarchy_RegionTypes";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:52:"aEmployeeRole_Organization_RegionalHierarchy_Regions";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:69:"aEmployeeRole_Organization_RegionalHierarchy_Regions_RegionStatistics";a:2:{i:0;i:0;i:2;i:0;}s:82:"aEmployeeRole_Organization_RegionalHierarchy_Regions_    17               7  87987687:1:"2015-05-07Em       9               7  4354334Station2015-05-07:{
         7  Naveed     Ahmed          0         0  847893       hfkjhfskj     fjksddshkfjdshfkj  2015-04-29 14:22:16                    19  O:16:"clsEmployeeRoles":68:{s:56:"aEmployeeRole_Organization_RegionalHierarchy_RegionTypes";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:52:"aEmployeeRole_Organization_RegionalHierarchy_Regions";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:69:"aEmployeeRole_Organization_RegionalHierarchy_Regions_RegionStatistics";a:2:{i:0;i:0;i:2;i:0;}s:82:"aEmployeeRole_Organization_RegionalHierarchy_Regions_    17               7  87987687:1:"2015-05-07Em      10               7  896789798ation2015-05-07:{

I have attached the pic of the output i am getting... tables are manufacturer,loan,refund, manufacutrerId is common in all tables. now in the pic it shows repeated record as the manufacturer took loan 2 times but return amount 1 time.. but it repeats in refund column. Please Help !!!

Answer 1

This query should work:

SELECT ManufacturerId,FirstName,LA,RA, LA - RA as RemainingAmount FROM  (SELECT MM.ManufacturerId,MM. FirstName,SUM(LoanAmount) as LA, SUM(RefundAmount) as RA  FROM microfinance_manufacturers AS MM 
                INNER JOIN manufacturer_loans AS ML ON MM.ManufacturerId = Ml.ManufacturerId 
                INNER JOIN manufacturer_refunds AS MR ON MM.ManufacturerId = MR.manufacturerId
                GROUP BY MM.ManufacturerId) as a

Answer 2

You need to do the aggregations before the join . Otherwise, you end up with a cartesian product that throws off the values:

SELECT MM.*, ML.*, MR.* 
FROM microfinance_manufacturers MM left join
     (select Ml.ManufacturerId, count(*) as numloans, sum(ml.amount) as loanamount
      from manufacturer_loans ML
      group by ManufacturerId
     ) ml
     on MM.ManufacturerId = Ml.ManufacturerId left join
     (select Mr.ManufacturerId, count(*) as numrefunds, sum(ml.amount) as refundamount
      from manufacturer_refunds mr
      group by ManufacturerId
     ) mr
     on MM.ManufacturerId = MR.manufacturerId;

Your question is unclear both on the data layout and on the expected results. But this should be basically what you need.